Token Generator Subsystem for Reinforcement Learning Text Generation

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Solution Overview

Problem

Reinforcement learning-based controlled natural language generation systems face challenges with 'sparse rewards' that are only available at the output sentence level, leading to poor performance in tasks like text style transfer, as they require rewards at the output token level for precise feedback.

Innovation Solution

A system and method that incorporate a token generator subsystem, attention layer, scoring layer, reward generation layer, and feedback score generation layer to provide dense rewards and feedback scores for each output token, enabling precise token-level feedback and improving the quality of generated text.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rollout strategy is used to overcome sparse rewards, then token-level rewards can be obtained, but precise reward assignment is not achieved leading to poor performance

Engineering Contradiction:
Improvereward assignment precisionVSAvoidsystem performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the generated output is evaluated by a critic model that provides dense rewards at each token generation step. The critic model compares the generated token with the target style and provides immediate feedback, enabling precise reward assignment that guides the generator model to improve its output quality iteratively.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces a critic model as an intermediary between the generator model and the reward signal. This critic model acts as a mediator that evaluates the generated tokens and translates the sparse sentence-level rewards into dense token-level rewards, enabling precise feedback without requiring direct access to parallel corpus data.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If dense rewards are provided at token level, then precise feedback is achieved, but system complexity increases

Engineering Contradiction:
Improvefeedback precisionVSAvoidsystem architecture complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the natural language processing task into distinct components: a generator model that produces tokens, a critic model that evaluates tokens, and a reinforcement learning module that updates policies. This segmentation allows each component to specialize in one function, achieving precise token-level feedback while managing system complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The critic model serves as an intermediary that simplifies the complex task of evaluating generated tokens. Instead of implementing complex evaluation logic in the generator, the critic model handles the sophisticated analysis of token quality, style adherence, and fluency, thereby achieving precise feedback without overcomplicating the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11586830B2System and method for reinforcement learning based controlled natural language generation
Publication Date: 2023.02.21 COINBASE INC
  • US11586830B2 patent drawing
  • US11586830B2 patent drawing
  • US11586830B2 patent drawing

AI summary

A system for reinforcement learning based controlled natural language generation is disclosed. The system includes a token generator subsystem to generate an initial output phrase including a sequence of output tokens. The system includes trained models associated with corresponding predefined tasks. Each trained model includes an attention layer to compute attention-based weights for each output token. The trained models include a scoring layer to generate a phrase sequence level score for the output phrase. The trained models include a reward generation layer to generate dense rewards for each output token based on the attention-based weights and the phrase sequence level score. The trained models include a feedback score generation layer to generate a feedback score based on the dense rewards and reward weights assigned to the dense rewards of the corresponding trained models. The feedback score generation layer provides the feedback score iteratively to the token generator subsystem.